Spinning Rotor for an Open-End Spinning Machine having a Friction-Enhancing Lining Made of an Elastomeric Material, and Open-End Spinning Machine

ABSTRACT

A spinning rotor for an open-end spinning device includes a rotor shaft, via which the spinning rotor is driven with the aid of a belt. A contact area is on the rotor shaft for engagement with the belt. A friction coefficient-increasing lining made of an elastomeric material is applied along at least part of the contact area.

FIELD OF THE INVENTION

The present invention relates to a spinning rotor for an open-end spinning device, comprising a rotor shaft, via which the spinning rotor is driven with the aid of a belt, in particular, a tangential belt. The rotor shaft includes a contact area for the belt.

BACKGROUND

With respect to spinning rotors of open-end spinning machines, it has been common for a long time to drive these spinning rotors with the aid of a tangential belt which rests against the shaft of the spinning rotor. The spinning rotors are usually mounted on support disks in this case. The belt is generally pressed against the rotor shaft in this case with the aid of an additional drive roller in order to reduce the slip between the belt and the rotor shaft. In this case, it can also be provided to change the contact pressure of the pressure roller in order, for example, to provide for a faster ramp-up of the spinning rotors or to enable an adaptation to different spinning materials or the like. Such an open-end spinning device comprising a pressure roller onto which a different contact pressure can be applied is described, for example, in DE 101 07 254 A1. Due to the slip between the belt and the rotor shaft, wear can occur on the belt as well as the spinning rotor, however, despite the pressure roller.

In order to reduce the wear of the rotor shaft of the open-end spinning rotor, it has already been proposed to provide the rotor shaft with a wear-reducing coating in the contact area of the tangential belt. Due to a wear of the belt, however, there may nevertheless be an insufficient force transmission between the belt and the rotor shaft, and so the spinning rotors can only be accelerated very slowly or may never even reach their operating speed. If the contact pressure of the pressure roller is increased in this case, this force not only acts on the tangential belt and the rotor shaft, but the rotor shaft is also simultaneously pressed more strongly into the wedge gap of the support disks. This results in increased flexing work in the lining of the support disks, which results in considerable energy consumption in the area of the rotor bearing. This has a negative effect, in particular, in the case of the present-day spinning machines comprising increasingly faster running open-end spinning rotors having rotational speeds of 170,000 1/min and higher.

SUMMARY OF THE INVENTION

A problem addressed by the present invention is therefore that of providing a spinning rotor and an open-end spinning device which can be operated with lower energy consumption. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

The problems are solved with the aid of a spinning rotor with the features described and claimed herein.

A spinning rotor for an open-end spinning device includes a rotor shaft, via which the spinning rotor is driven with the aid of a belt, in particular, a tangential belt. The rotor shaft includes a contact area for the belt in this case. It is now provided that the contact area of the spinning rotor is provided with a friction coefficient-increasing lining made of an elastomeric material. The term “friction coefficient-increasing” is understood to mean, in this case, an increase in the friction coefficient with respect to the base material and/or the surface material of the shaft. An “elastomeric material” is understood, within the scope of the present invention, to be an elastically deformable material based on plastic or rubber. A material is elastically deformable when it has a modulus of elasticity of less than 1000 MPa.

If the spinning rotor is provided with the friction coefficient-increasing lining in the contact area of the belt, the contact pressure of the pressure roller can be reduced, wherein good force transmission is nevertheless achieved between the belt and the spinning rotor. The load on the spinning rotor between the two bearing points is reduced as a result, and so the flexing work in the support disks and, therefore, the energy consumption of the spinning device can be reduced. It is also particularly advantageous, in this case, that the radial bearing load of the support disk bearing is also reduced as a result and, therefore, the service life of the bearings is extended. Since the friction coefficient-increasing lining is made of an elastomeric material, which has a particularly favorable friction coefficient relative to the driving belt, the slip between the belt and the rotor shaft and, therefore, the energy consumption and the wear of the belt can be reduced to a particularly great extent. In addition, such materials have favorable damping properties and the manufacture of the spinning rotor can be carried out particularly cost-effectively as compared to a coating comprising other friction coefficient-increasing materials.

According to one embodiment of the invention, it is advantageous when the lining has an overall width which is less than the width of the belt provided for driving the spinning rotor. As a result, the lateral edge areas of the belt do not rest on the lining, but rather on the base material of the rotor shaft, whereby the lining is protected against damages caused by the belt.

According to a first embodiment of the invention, the lining can be continuously applied across the entire effective width of the lining. According to another embodiment, it is also conceivable, however, that the lining is applied onto the rotor shaft in the form of multiple strips situated next to one another and spaced apart from one another relative to the axial direction of the rotor shaft. It is advantageous in this case that the rotor shaft having such a design undergoes less weakening.

Moreover, it is advantageous when the lining has a lining thickness of at most 1 mm, preferably at most 0.75 mm and, particularly preferably, at most 0.5 mm. The flexing work in the rotor drive and, therefore, the energy consumption, can be further reduced as a result.

Moreover, it is advantageous when the at least one recess is designed as at least one circumferential groove. In the simplest variant, the circumferential groove can be designed as a rectangular groove in this case, into which the plastic material has been introduced, in particular, via vulcanization. The lining is subjected to only slight wear as a result. In this case, it is also advantageous when the lining thickness is at most 1 mm, preferably at most 0.75 mm and, particularly preferably, at most 0.5 mm. The depth of the recess can be limited as a result and a weakening of the spinning rotor, which would reduce its characteristic frequency and result in undesirable oscillations during operation, can be avoided as a result. In this embodiment as well, the lining can be continuously applied or in the form of interspaced strips or rings.

In order to provide a preferably smooth outer surface of the rotor shaft and, therefore, a preferably planar support surface for the belt, it is furthermore advantageous when the rotor shaft, including the introduced lining, is ground. As a result, the force transmission between the belt and the rotor shaft can be improved and wear of the belt and of the rotor shaft can be reduced.

It is particularly advantageous when the lining is made of nitrile rubber or of hydrogenated acrylonitrile butadiene rubber. This not only has the friction and damping properties which are favorable for the operation of the spinning rotor, but is also antistatic, and so trash deposits in the area of the lining can be avoided. A close fit of the belt on the rotor shaft and, therefore, good force transmission between the belt and the rotor are further enhanced as a result. It is also conceivable, however, that the lining is made of a polyurethane elastomer or a natural rubber. These also have a favorable friction coefficient with respect to the drive belt and therefore provide for an energy-saving and low-wear operation of the open-end spinning device.

It is also advantageous when the rotor shaft is made of a metal, in particular, an aluminum material or a steel material. The heat, which still forms in the lining due to the flexing work between the belt and the lining, can be dissipated in a particularly favorable way as a result.

Such a spinning rotor comprising a rotor shaft which is provided with a friction coefficient-increasing material in its contact area can be utilized particularly advantageously for the energy-saving and low-maintenance operation of an open-end spinning device. Therefore, protection for an open-end spinning device comprising such a spinning rotor is also claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages of the invention are described with reference to the exemplary embodiments represented in the following. Wherein:

FIG. 1 shows a schematic top view of an overview representation of an open-end spinning device comprising a rotor shaft and a belt for driving the rotor shaft;

FIG. 2 shows a detailed representation of a spinning rotor including a contact area for a belt;

FIG. 3 shows a partial cutaway view of one further embodiment of a spinning rotor comprising a friction coefficient-increasing lining; and

FIG. 4 shows a partial cutaway view of one further, alternative embodiment of a spinning rotor.

DETAILED DESCRIPTION

Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

FIG. 1 shows a schematic top view of an open-end spinning device 4 comprising a spinning rotor 1 and a belt 3 for driving the spinning rotor 1. In this case, the spinning rotor 1 usually consists of the rotor shaft 2 and a rotor cup 6, which can be removably as well as fixedly connected to the rotor shaft 2. The spinning device 4 includes, in the usual way, a bearing device for the spinning rotor 1, which is designed in the form of a support disk bearing in this case. Two support disk bearings 13, in each of which, in turn, a shaft 14 is mounted, are accommodated in a bearing block 12 for the radial support of the spinning rotor. Each of the two shafts 14 supports a support disk 10 at each of its two ends. The two shafts 14 comprising the support disks 10 are now situated in such a way that a wedge gap 9 forms between two support disks 10 in each case, in which the spinning rotor 1, including its rotor shaft 2, can be accommodated. The drive of the spinning rotor 1 takes place between the two resultant pairs of support disks with the aid of the belt 3 which tangentially contacts the rotor shaft 2, as in this case, or only slightly wraps around the rotor shaft 2.

During operation, the spinning rotor 1 rotates at speeds of 170,000 1/min and higher. In the case of a belt drive as described, considerable contact pressures are required in order to press the belt 3 against the rotor shaft 2 of the spinning rotor 1 and thereby transmit the motion of the belt 3 onto the spinning rotor 1 and make it possible to accelerate the spinning rotor 1 to the required speed. Due to these driving forces, however, the spinning rotor 1 is also pressed deeper into the wedge gap 9 of the support disks 10, and so, as the contact pressures increase, the deformation work in the lining of the support disks 10 also increases to a considerable extent. This results in an undesirably high temperature development in the lining of the support disks 10, which promotes an uneven running of the spinning rotor and wear of the support disks 10. In addition, this flexing work also results in considerable energy consumption in the mounting of the spinning rotor 1. On the other hand, slip occurs between the belt 3 and the rotor shaft 2, however, in particular during the ramping-up of the spinning rotor 1, which, over time, can result in considerable wear of the belt 3. As a result, the spinning rotors 1 can be accelerated only very slowly, for example, during piecing, or the required speed for the piecing, and possibly even the operating speed, cannot even be reached any more and, under certain circumstances, a faulty yarn is produced.

It is therefore proposed to provide the rotor shaft 2 of the spinning rotor 1 with an elastomeric, friction coefficient-increasing lining. FIG. 2 shows such a spinning rotor 1 which is provided with such a friction coefficient-increasing lining 8 in the contact area 7, i.e., the effective area of the drive belt 3. As a result, the friction coefficient between the belt 3 and the rotor shaft 2 is considerably improved or even doubled with respect to a conventional contact area, and so substantially lower contact pressures are required on the pressure roller (not shown) in order to reliably transmit the motion of the belt 3 onto the rotor shaft 2. Due to the reduced pressing force of the pressure roller, the spinning rotor 1 is also pressed into the wedge gap 9 of the support disks 10 to a lesser extent, which results in a considerable energy reduction due to the greatly reduced flexing work in the support disks 10. In addition, due to the reduced contact pressure of the belt 3 onto the rotor shaft 2, the radial load on the support disk bearings 13 is also reduced, and so the support disk bearings 13 are also subject to substantially less wear and require replacement less often. In addition, due to the improvement in the friction coefficient, the wear of the belt 3 is also reduced, whereby the belt 3 also has a substantially longer service life and, therefore, the amount of maintenance work can be further reduced.

According to the present example, the overall width b of the lining 8 is selected to be less than the width B of the belt 3 (see FIG. 1). As a result, on the one hand, the belt 3 can form a highly favorable friction coefficient pairing with the lining 8, although the belt 3 no longer rests, via its lateral edges 15 (see FIGS. 3 and 4), on the lining 8, but rather on the surrounding cylindrical surface of the rotor shaft 2. Premature wear of the lining 8 due to the abrasive edges 15 of the belt 3 can be avoided as a result, and so the service life of the spinning rotor 1 can also be improved. In the event of wear, however, the lining 8 can be replaced in a comparatively simple and cost-effective way. Moreover, the lining thickness d (see FIGS. 3 and 4) is relatively thin in this case, preferably having a lining thickness d of at most 0.3 mm, in order to avoid unfavorable flexing work in the lining 8.

FIG. 3 shows a partial cutaway view of a further embodiment of a spinning rotor 2, in the case of which the lining 8 is introduced, in the form of an insert, into a recess 5 of the rotor shaft 2. As is apparent in the figure, the lining 8 is introduced into the recess 5 in such a way that the lining 8 forms a smooth surface together with the surrounding cylindrical surface of the rotor shaft 2. The smooth, planar surface of the rotor shaft 2 in the area of the lining 8 and, in particular, at the transitions between the lining 8 and the cylindrical surface of the rotor shaft 2 can be produced, for example, via grinding. In this embodiment as well, the lining 8 is protected in a particularly favorable way against excess wear by the edges 15 of the belt 3. Nevertheless, a replacement of the lining 8 is also possible in a simple and cost-effective way in this case.

The lining thickness d or the depth of the recess 5 should be selected to be relatively small in this case as well, in particular, in a range of less than 1 mm, in order to avoid unfavorable influences on the characteristic frequency of the spinning rotor 1 and, therefore, undesirable oscillations.

Finally, FIG. 4 shows one further embodiment of a spinning rotor 1, in which the lining 8 is not applied continuously across the overall width b of the lining, but rather in the form of lining rings which are spaced apart from one another and, in combination, provide the overall width b of the lining 8. For this purpose, the rotor shaft 2 is provided with multiple interspaced recesses 5, in the form of circumferential grooves in this case, into each of which a lining ring has been introduced. In this embodiment as well, it is advantageous when the lining 8 is designed to have only a very small lining thickness d. A lining thickness d of less than 1 mm, or preferably only a few tenths of a millimeter, for example, at most 0.3 mm, is also advantageous in this case.

With the aid of the described lining 8, not only considerable energy savings can be achieved and the wear can be reduced. Due to the improved transmission of motion from the belt 3 onto the rotor shaft 2, the acceleration times for the spinning rotor 1 during piecing can also be considerably shortened, and so the machine efficiency is also improved as a result. Likewise, the operating speeds of the spinning rotor 1 can also be reached faster and more reliably, and they can be held constant. The improved embodiment of the spinning rotor 2 comprising a friction coefficient-increasing lining therefore also contributes to the production of a higher-quality yarn.

The invention is not limited to the exemplary embodiments which have been represented. Modifications and combinations within the scope of the claims are also covered by the invention.

LIST OF REFERENCE SIGNS

1. spinning rotor

2. rotor shaft

3. belt

4. open-end spinning device

5. recess

6. rotor cup

7. contact area

8. lining

9. wedge gap

10. support disk

11. axial bearing

12. bearing block

13. support disk bearing

14. shaft

15. lateral edges of the belt

b overall width of the lining

B width of the belt

d lining thickness 

1-10. (canceled)
 11. A spinning rotor for an open-end spinning device, the spinning rotor comprising: a rotor shaft, via which the spinning rotor is driven with the aid of a belt; a contact area on the rotor shaft for the belt; and a friction coefficient-increasing lining made of an elastomeric material along at least part of the contact area.
 12. The spinning rotor as in claim 11, wherein the lining comprises an overall width (b) that is less than a width (B) of the belt provided for driving the spinning rotor.
 13. The spinning rotor as in claim 11, wherein lining is applied onto the rotor shaft as multiple spaced-apart strips.
 14. The spinning rotor as in claim 11, wherein the lining comprises a thickness (d) of 1 mm or less.
 15. The spinning rotor as in claim 11, further comprising at least one recess formed in the rotor shaft in the contact area, the lining contained in the recess.
 16. The spinning rotor as in claim 15, wherein the lining is co-planar with adjacent surfaces of the rotor shaft via grinding of the rotor shaft and lining.
 17. The spinning rotor as in claim 11, wherein the fining is formed from nitrile rubber (NBR) or hydrogenated acrylonitrile butadiene rubber (HNBR).
 18. The spinning rotor as in claim 11, wherein the lining is formed of a polyurethane elastomer (PUR).
 19. The spinning rotor as in claim 11, wherein the rotor shaft is made of a metal.
 20. An open-end spinning device comprising a spinning rotor and a driving belt, wherein the spinning rotor is in accordance with claim
 11. 